> The lack of background music and pace is really interesting to me. Compared to a typical "how it's made" video [1] (which I feel has a similar level of detail), this video feels significantly more digestible. Those moments of silence feel totally alien and out of place in today's style, but I think contributes positively to my ability to understand and process the information.

I think that's because the older movie is an actual educational movie, while the video you linked is really pseudo-educational entertainment. An educational video has the goal of leaving the viewer with actual understanding of something, while the pseudo-educational video only cares to vaguely tickle the viewer's curiosity, and is fine to leave them nearly as ignorant as when they started. While the two movies may have a "similar level of detail," the educational video focuses on fully explaining a specific problem and solution, while the pseudo-educational video only vaguely skims through the high-level steps of some manufacturing process and barely even explains what the product is for.

http://www.engineerguy.com/ makes educational videos similar to this 1937 movie on a lot of similar topics.